I think it is a better weapon, than the G36 or M-16.
Three points out of my experience with 5,56 mm and 7,62 mm weapons are, that 5,56 mm weapons are a lot of lighter to wear, that 7,62 mm weapons are more accurate, because of the greater weight of the projectile and in the end, that the lower cadence of 7,62 mm weapons makes them more usefull in the field.
In fact you didn't need bursts in most situations. But mostly it is only a waste of precious ammunition.
So I would choose in every case a 7,62 mm weapon like G3 or SR 25 over a 5,56 mm weapon.
Oh I forgot one important point. The G3 has some own weight and is longer than the G36, so if you have to use a bayonet it goes well used even through body armor.
And the G36 crashed lots of times during the training of urban warfare. Never heard something like this of the G3 and of cause it never happens me personally.
So you could use the G3 even as an elevator (with another soldier together) for one soldier in order to bring him to a higher window. G36 crashed several times.
But the optic sight of the G36 was the best I ever saw. Specially at night. If they would combine it with the G3, you would have the ultimative weapon. Imo.